The current study endeavored to closely compare the detection rate of 68-Gallium labelled prostate-specific membrane antigen ([⁶⁸Ga]Ga-PSMA) versus [¹⁸F]Fluorocholine in men with prostate cancer (PC), to investigate the benefits and pitfalls of each modality in the setting of various patient characteristics. We retrospectively analyzed 29 biopsy-proven PC patients in two categories, staging and restaging, who underwent both scans within a maximum of 30 days of each other. Variables including patient demographics, prostate specific antigen (PSA) level, Gleason score, clinical course, and following treatments were recorded. The number and location of suspicious lesions as well as uptake values were noted. A total of 148 suspicious lesions were detected, of which 70.9% (105/148) were concordantly visualized in both imaging modalities. [⁶⁸Ga]Ga-PSMA positron emission tomography/computed tomography (PET/CT) revealed a higher number of metastatic lesions per patients (91% vs 78%). The mean of maximum standardized uptake value (SUV max) in concordant lesions was significantly higher in [⁶⁸Ga]Ga-PSMA compared to [¹⁸F]Fluorocholine PET/CT (14.6 ± 8.44 vs. 6.9 ± 3.4, p = 0.001). Discordant lesions were detected by both modalities, but more frequently by [⁶⁸Ga]Ga-PSMA PET/CT (20.3% in [⁶⁸Ga]Ga-PSMA versus 8.8% by [¹⁸F]Fluorocholine PET/CT). In patients with PSA levels below 1.0 ng/mL and <2.0 ng/mL, [¹⁸F]Fluorocholine PET/CT detection rate was half (57% and 55%, respectively) that of [⁶⁸Ga]Ga-PSMA PET/CT. Tumor, nodes and metastases (TNM) staging, and subsequently patient management, was only influenced in 4/29 patients (14%), particularly by [⁶⁸Ga]Ga-PSMA PET/CT with PSA values under 0.5 ng/mL. [⁶⁸Ga]Ga-PSMA PET/CT revealed superior diagnostic performance to [¹⁸F]Fluorocholine PET/CT in staging and restaging of PC patients, especially in cases with low PSA levels. However, in a few hormone resistant high-risk PC patients, [¹⁸F]Fluorocholine PET/CT may improve overall diagnostic accuracy.

A 53-year-old man with previous history of sigmoid colon adenocarcinoma who had undergone surgical resection and adjuvant chemotherapy presented with slightly rising carcinoembryonic antigen (CEA), while anatomical imaging modalities were unremarkable. FDG PET-CT study did not identify residual tumoral disease; however, there were abnormalities in the gallbladder most likely suggestive of cholecystitis. Eight weeks after cholecystectomy, serum CEA concentration reached normal values. Final histopathology of the gallbladder was also consistent with acute on chronic cholecystitis.

Osteonecrosis (avascular necrosis, AVN) is a disabling complication of corticosteroid exposure and is well recognized in adolescents treated for hematologic malignancies, including acute lymphoblastic leukemia (ALL). We report a 17‐year‐old female with ALL and later acute myelogenous leukemia (AML) after hematopoietic stem cell transplantation (HSCT), who received documented post‐HSCT prednisolone therapy and presented with progressive bilateral knee pain. MRI demonstrated multifocal osteonecrosis involving both distal femoral condyles and proximal tibiae, with classic serpiginous infarct morphology and a double‐line sign. A [99mTc]‐MDP three‐phase bone scan with hybrid SPECT/CT demonstrated discordant activity: intense uptake and marked sclerosis in the femoral condyles but minimal uptake in the tibial lesions. This pattern may reflect heterogeneous lesion activity or different reparative stages rather than a validated predictor of collapse. The case highlights the potential value of bone scintigraphy/SPECT/CT as an adjunct to MRI for lesion activity mapping and surveillance planning in selected high‐risk pediatric oncology patients while emphasizing that its prognostic role requires longitudinal validation.

Prolidase deficiency (PD) is a rare autosomal recessive metabolic disorder caused by pathogenic variants in the PEPD gene, which is responsible for making prolidase and collagen resynthesize. It leads to a wide range of clinical symptoms, including skin ulcers, intellectual disability, and recurrent infections. Diagnostics are based on the presence of dipeptides in the urine and prolidase activity in various cells, as well as the detection of the pathogenic variant in the PEPD gene; however, no standard method is currently known for its diagnosis nor for its treatment. Case 1 presents a 17‐year‐old male with dyspnea, cyanosis, and pulmonary arteriovenous malformations (AVMs), an atypical presentation for PD. Case 2, a one‐year‐old female with fever, seizures, productive coughs, erythematous ulcers, and developmental delays, highlights the disease’s broad symptoms. This study widens our understanding of PD, especially for lesser‐known populations, such as the population in Iran. It indicates considering PD in the differential diagnosis of various diseases and also a global collaboration for managing PD. The study also recommends a standard approach to diagnosing PD and a personal management system due to its broad manifestations. In addition, it indicates the need to consider different ethnic and geographical groups in future PD studies to further enhance our understanding of this rare disease.

To explore a functional anteroposterior pelvis diameter (APD) cutoff for diagnosing hydronephrosis (HDN) in the pediatric population, and to evaluate the correlation between structural and functional renal parenchymal thickness (PT) measured by ultrasonography (US) and technetium-99m dimercaptosuccinic acid single-photon emission CT (^99mTc-DMSA SPECT), respectively. This single-center cohort study enrolled 76 pediatric patients (152 kidney units) referred to the Department of Nuclear Medicine of Children's Medical Center. Structural and functional PT were measured by US and ^99mTc-DMSA SPECT, respectively. The ^99mTc-DMSA SPECT was assessed by a pediatric nuclear medicine specialist blinded to the US findings. The ^99mTc-DMSA SPECT and US were performed on the same day. The correlation between structural and functional PT measurements was evaluated through the Spearman correlation analysis while the functional APD cutoff for HDN diagnosis was established by using the receiver operating characteristic curve. The study demonstrated a poor to moderate relationship between structural and functional PT (Spearman's rho=0.30–0.52, p<0.05). A functional APD cutoff of 14 mm in the ^99mTc-DMSA SPECT was in concordance with the ultrasonographic cutoff of 10 mm for diagnosing HDN. This study can give the experts new insights into using the ^99mTc-DMSA SPECT as an additional modality in measuring the functional renal dimensions, especially PT alongside the US findings.